The present embodiments relate to transmission of data between a rotor and a stator.
Data may be wirelessly transmitted between system parts rotating in relation to one another, for example, in rotation machines of power stations, large motors, radar systems or computer tomography systems. A transmitter or receiver is arranged on the rotor and stator, respectively. The data is transmitted between the rotor and stator optically or capacitively. If there is an area in the vicinity of the axis of rotation of the rotor not available for data transmission, since for example—as in a computer tomography system—this must remain empty, the data transmission takes place in the radially outer area of the rotor. Data transmission that takes place in the radially outer area of the rotor imposes greater demands on the device for transmission of data with respect to the communication link between transmitter and receiver. The data rate to be transmitted may continue to increase, since image processing systems operate with data streams of up to 1011 bits/second.
DE 28 46 526 A1 discloses using an optical fiber as an extended receiver. Light is guided at least partly in the optical fiber to the receiver being coupled into this conductor from the side by introduction of discontinuities. The optical fiber may be implemented as a circle segment or as a complete loop. When one or more transmitter elements are used, an uninterruptible transmission is guaranteed during a rotational movement of the rotor. Once light has been coupled into the optical fiber, the light is partly coupled out again at its discontinuities, so that, depending on the length of the conductor through which it passes, more or less light gets lost for the transmission.
DE 32 05 065 A1 discloses a receive element in the form of an annular reflective valley. Light, which is routed to a receive unit via multiple reflection, can be coupled into this valley in an almost tangential direction at any angular position. Implementing this type of reflective valley is complicated and cost-intensive. Absorption in the reflective valley may cause losses in the systems.
To keep such transmission power losses low, DE 42 18 692 A1 discloses a number of transmitter units and receiver units that are located opposite one another directly or by a mirror in the transmission position. The transmitter and receiver unit have a practically tangential orientation. The number of transmitter and receiver units may be small with a large free internal diameter. A phase jump may occur in data transmission during a switch between a transmit unit currently involved in transmission and a subsequent transmit unit—on account of the greater distance between the subsequent transmit unit and the receiver unit. The maximum transmissible data rate is restricted. To compensate for the phase jump, DE 103 02 435 A1 discloses a repeated transmission of data bits, which is controlled by a control unit.